Find a reasonable diameter bolt or screw that will make contact with the terminals in the device you are using. [I have used an old bicycle axle.] Cut it to length with a hacksaw. Use a dremel grinding wheel to smooth off the rough edges. If you want, use the dremel to make a domed positive end and a flat negative end. Wrap the cut piece in duct tape until its outside diameter matches the outside diameter of the battery you are replacing. Use a knife to trim the duct tape back so the "terminal" ends protrude just the right amount. It is cheap, "dirty" method, but effective. I have done this successfully for a AA cell and a CR123 sized spacer. The dummy cell ends up heavier than a battery because of the heavy bolt plus the weight of the duct tape.
EssLight
